Ledyard - It was sometime after he underwent brain surgery to remove a malignant tumor that Jeremiah Kalbach announced he would graduate on time and with his classmates at Ledyard High School.

He was told it would be no small feat and there was a good likelihood of staying back a year. But he remained undeterred.

Kalbach missed all of his freshman year and much of his sophomore year while undergoing chemotherapy and radiation treatment, among other procedures, that would leave him underweight, weak and generally lacking stamina.

He compensated by catching up with a tutor at home and taking online classes. Cancer free, he rejoined his classmates during his sophomore year and said he is "ecstatic" to be accepting his diploma on June 21.

Kalbach's inspirational comeback is a testament to his perseverance and upbeat attitude, according to Director of Guidance David Doyle.

"He's a great kid, very pleasant and always upbeat, even through the most difficult trying times," Doyle said. "After what he's gone through he's remained positive and visits the office telling jokes. He has an incredibly positive attitude."

Kalbach's illness first came to light at the age of 14 while in the eighth grade. He started experiencing bouts of nausea and vomiting while playing lacrosse, a sport he loves but has since had to give up.

Doctors couldn't immediately pinpoint the problem. Meanwhile, his sickness became more frequent. His mother, Elizabeth Kalbach, said doctors had at first prescribed medicine to combat acid reflux.

Then headaches started and grew progressively worse as 2010 progressed.

Eventually, a pediatrician sent Kalbach for a CT scan at The William W. Backus Hospital where the brain tumor was discovered.

She said no one in the family had much time for doom and gloom. They were immediately sent to Yale-New Haven Hospital for surgery.

Kalbach remembers feeling relief that there was finally a diagnosis after months of uncertainty and suffering. Still, he said, he cried on the way to Yale. He remembers his mother repeatedly telling him that "if she could have taken it she would."

The surgery to remove the brain tumor was successful. Kalbach spent several weeks in the hospital before traveling to a rehabilitation hospital in Boston for radiation treatment and later chemotherapy and physical therapy.

He said family and friends kept him in good spirits.

Kalbach said he handled the medicine well, better than what he would have expected. But he was a small kid to start with, and had shrunk to about 90 pounds at one point. He now has weekly physical therapy sessions at school.

Elizabeth Kalbach says the entire family - father, sister and brother - remained positive, kept faith in God and were buoyed by the support of family, friends and the medical and school community. Kalbach said he cherishes the giant poster signed by numerous students and friends, dozens of cards and a video of get-well wishes.

"It feels pretty fantastic to have had such a traumatic start and to work my way up to graduate with my peers," he said.

Several positives also came out of the experience, he said. He is now vice president of the Connecticut Chapter of the Kids and Families Impacting Disease to Research Science, a group that meets at various hospitals in an advisory role, suggesting how hospitals can be more innovative with research, particularly when it comes to children.

"We're trying to build a worldwide network of kids' groups … so that when someone starts a trial or study they can contact us and we can talk globally to 100 kids with things like sickle cell anemia or leukemia. They can ask us questions," he said.

The group has given feedback to Pfizer researchers and earlier this year set up a booth at a convention of the American Academy of Pediatrics in Vancouver, talking to researchers and pediatric oncologists and meeting with their Canadian counterparts.

"This is just the first year," he said. "It can get bigger and bigger and change the way medicine is done."

In addition to his work with the group, Kalbach and his mother both joined efficacy boards at Yale-New Haven.

"It feels great to give back," he said.

He said he was unable to join any team sports at school because they were just too physically draining. Instead, he discovered the Unified Sports team, where he has paired with intellectually challenged students in several sports.

As for his future career, Kalbach said he now has a great appreciation for physical therapists and plans to explore something in the field as he works his way through classes at Three Rivers Community College in Norwich.